The following descriptions and examples are not admitted to be prior art by virtue of their inclusion within this section.
In a seismic survey, a source may be actuated to generate seismic energy, and the resultant seismic wavefield may be sampled by an array of seismic receivers disposed at a distance from the seismic source. Each receiver may be configured to acquire seismic data, which are normally in the form of a record or trace representing the value of some characteristic of the seismic wavefield against time. The acquired seismic data are a representation of the seismic wavefield at the receiver location. Information about the earth's sub-surface can be obtained from the acquired seismic data.
One well-known type of a seismic receiver is the seismic geophone. A geophone contains one or more sensors mounted in a casing. A geophone may be a single component geophone, which contains one sensor that records the component of the seismic wavefield parallel to a pre-determined direction. Information about the vertical component of the seismic wavefield may be obtained using a single component geophone oriented such that the sensing direction of the geophone is substantially vertical. Alternatively, a geophone may be a three-component geophone which includes three sensors oriented to record the components of the seismic wavefield in three orthogonal directions, which are typically denoted as x, y and z components.
Three-component seismic data are commonly displayed on three separate plots. Consequently, it is often difficult to jointly interpret all three components at the same time. However, joint interpretation of two components may be possible using hodogram displays, where the seismic data are windowed in time and offset, and both components are plotted in one display. The resulting ellipses may be analyzed for the length and orientation of their half axes to obtain information about the wave mode of the seismic data. This method, however, often results in substantial degradation of the temporal and spatial resolution of the result, due to its requirement of windowing the data.